CN110178322A - High-resolution interpolation device for optical encoder - Google Patents
High-resolution interpolation device for optical encoder Download PDFInfo
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- CN110178322A CN110178322A CN201780065692.XA CN201780065692A CN110178322A CN 110178322 A CN110178322 A CN 110178322A CN 201780065692 A CN201780065692 A CN 201780065692A CN 110178322 A CN110178322 A CN 110178322A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/347—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
- G01D5/3473—Circular or rotary encoders
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/50—Transmitters
- H04B10/516—Details of coding or modulation
- H04B10/54—Intensity modulation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
- G01D5/24404—Interpolation using high frequency signals
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/347—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
- G01D5/34746—Linear encoders
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/60—Receivers
- H04B10/61—Coherent receivers
- H04B10/616—Details of the electronic signal processing in coherent optical receivers
Abstract
A kind of equipment includes optical modulator, is configured to respond to the first electric signal and baseline optical signal and generates the first and second modulated optical signals.The equipment further comprises phase detectors, it is configured as receiving the first and second encoded optical signals and the first and second modulated opticals signal, and generates the second electric signal for indicating the phase difference between the encoded optical signals and the modulated optical signal.The equipment further comprises the voltage controlled oscillator for being configured to respond to second electric signal and generating electric pulse, and is configured as the counter counted to the quantity of the electric pulse, generates counting.The first electric signal for going to the optical modulator is the derivative form of the counting or the counting.
Description
Cross reference to related applications
This application claims the priority for the U.S. Provisional Application No. 15/332,615 that on October 24th, 2016 submits, full text
It is incorporated herein by reference, as recorded below and is used for all applicable purposes.
Background technique
Optical encoder is used in being related to the mobile position displacement measurement in linear or angle.Typical optical encoding
Device is using the light source to code wheel or code with projecting beam.The movement of code wheel or code band carries out " coding " to the light beam, then
It is received by photodetector.Encoded light is converted to electric signal or code by the photodetector, then handled by circuit
To carry out position displacement measurement.In absolute encoder.The each output for carrying out self-encoding encoder corresponds to code wheel or code band only
One position.In incremental encoder, the output of encoder is then counting or the string of pulse.
Interpolation device is the significant components in optical encoder, because they improve the accuracy and resolution of optical encoder
Rate.The resolution ratio of interpolation device and frequency response directly influence the resolution ratio of optical encoder.It is some to be based on TTL (transistor-crystalline substance
Body pipe logic) traditional interpolator of comparator or ADC (analog-digital converter) do not provide the enough resolution ratio for High Speed System.
For example, they may have about 50 maximum interpolation factor.Interpolation device based on orthogonal electric phaselocked loop (QEPLL) can provide
About 70 interpolation factor.However, usually requiring ROM (read-only memory) and look-up table based on the interpolation device of QEPLL to generate
Reference waveform, this requires big chip or plate face area from rather than it is cost-effective.It is expected that improving to some extent in these areas.
Detailed description of the invention
When reading in conjunction with the drawings, aspect of the invention will be best understood from the following detailed description.It is wanted
, it is emphasized that various features are not drawn to scale according to the standard practices in industry.In fact, the size of various features can
Arbitrarily to be increased or reduced for the clear of discussion.
Fig. 1 is the simplified block diagram of the optical encoder in one embodiment according to the aspect of the disclosure.
What Fig. 2 illustrated Fig. 1 according to one embodiment includes the partial view of the optical encoder of transmission code device.
Fig. 3 illustrates the part view of the optical encoder including reflection code device of Fig. 1 according to one embodiment
Figure,.
Fig. 4 is the simplified block diagram of the optical modulator in the optical encoder according to Fig. 1 of one embodiment.
Fig. 5 illustrates the optics output of the optical modulator from Fig. 4 according to one embodiment.
Fig. 6 is the simplified block diagram of the phase detectors in the optical encoder according to Fig. 1 of one embodiment.
Fig. 7 and Fig. 8 shows the flow chart of the method for the execution optical encoding according to the aspect of the disclosure.
Fig. 9 shows the method for obtaining the electric signal for the operation in the method in Fig. 7-8 according to one embodiment
Flow chart.
Specific embodiment
The following disclosure provides many different embodiments of the different characteristic for example for implementing provided theme.Hereafter
It describes component and disposes the specific example of form to simplify the disclosure.Obviously, these are only examples and are not intended as limiting
System.If disclosure those skilled in the relevant arts will be realized that under normal circumstances, for described equipment, system, side
Any replacement of method and further modification and to any further application of the principle of the disclosure be all set completely it is conceivable.
For example, feature, component described in one embodiment and/or step can be retouched with the other embodiments about the disclosure
Feature, component and/or the step stated are combined to form another implementation according to the equipment of the disclosure, system or method
Example, even if such combination is not explicitly shown.In addition, for reasons of clarity, being used in some instances through attached drawing
Identical appended drawing reference refers to the same or similar part.
The disclosure relates generally to optical encoders and optical encoding methodologies.More specifically, this disclosure relates to one kind is used for
The interpolation device that is new and improving to some extent of incremental optical encoder.Each embodiment is other than electric component also in phaselocked loop
(PLL) optical modulator is used in.Therefore, PLL is quasi-optics (or quasi- electrical).The novel PLL provides high frequency sound
Should and noise suppressed, and improve the interpolation factor of interpolation device.In addition, in some applications, in existing electrical interpolation device
ROM compared with look-up table, which can be used lesser chip or plate face area.Therefore, some embodiments
It more can economically be manufactured than its reference object.
With reference to Fig. 1, the optical encoder (or optic-encoded system) constructed according to the aspect of the disclosure is shown
The schematic diagram of certain components in 100.In brief overview, the embodiment of optical encoder 100 includes light source 11, be can be
The code device 16 and interpolation device 15 of code wheel or code band.Interpolation device 15 includes quasi-optics PLL (QOPLL), is connected with closed loop
The optical modulator 14 that connects, phase detectors (PD) 13, loop filter (LF) 17, voltage control oscillator (EVCO) 8 and can
Inverse counter 9.Optical encoder 100 may include the unshowned other components of Fig. 1, such as power supply circuit, interface circuit and
Other appropriate components known in the art.
In operation, light source 11 projects one or more light beams, the code device 16 and then output to code device 16
Optical signalling SAi、SBiAnd Sref.Optical signalling SAiAnd SBiIt is encoded by code device 16, and optical signalling SrefIt then keeps not compiled
Code.In addition, optical signalling SAiAnd SBiOut-phase is at 90 degree in this embodiment.Interpolation device 15 receives and processes optical signalling SAi、SBi
And Sref.More specifically, optical modulator 14 utilizes electrical input signal θCNTModulated optical signal Sref, and generate two modulation
Optical signalling SArAnd SBr.In this embodiment, optical signalling SArAnd SBrSame out-phase is at 90 degree.Phase with photodetector
Detector 13 detects optical signalling SAiAnd SBrBetween (or SBiAnd SArBetween) phase difference.Circuit quilt in interpolation device 15
It is designed such as phase difference minimum.In other words, when QOPLL reaches steady state operation, optical signalling SArAnd SBrIn
Phase Tracking (or being locked as) optical signalling SAiAnd SBiPhase.Therefore, the output from EVCO 8 --- Vo_upAnd Vo_down
As optical signalling SAiAnd SBiInterpolation electric signal.Compared with the existing interpolation device based on QEPLL, interpolation device 15 can be with structure
It makes more compact, and higher frequency response is provided.The detailed knot of each of said modules is discussed further below
Structure and operation.
In one embodiment, light source 11 includes light emitting diode (LED).In another embodiment, light source 11 includes
Generate the semiconductor laser of coherent light.The wavelength or spectrum and code device 16, optical modulator of light caused by light source 11
Various photodetectors in 14 and PD 13 compatibly work.Light source 11 may further include one or more collimating optics
Device (for example, in transmission optics encoder) or one or more focusing optics are (for example, in reflective optical encoder
In).
Code device 16 can between light source and interpolation device 15 angularly (for example, rotary motion caused by code wheel) or
Linearly (for example, code is with caused linear movement) is mobile.In addition, code device 16 can the light caused by light source 11 be
It is transmission or reflection.It illustrates in Fig. 2 and is compiled according to the optics with transmission code device 16 that the aspect of the disclosure is constructed
The example of code device 100.The optical encoding with reflection code device 16 constructed according to the aspect of the disclosure is illustrated in Fig. 3
Another example of device 100.
With reference to Fig. 2, which illustrates one in the optical encoder 100 with transmission code device 16 according to embodiment
The perspective view of a little components.Code device 16 (for example, code wheel or code band) includes at least two track Tr1 and Tr2.Track Tr1 tool
There are alternate light transmission and opaque region (or band), they are respectively as indicated by white and dark-coloured space.Each light transmission
There is width " D " along the direction of motion 126 with opaque region.It is " 2D " that light transmission and opaque region, which were formd with the period,
Periodicity pattern.
The partial view of phase detectors (PD) 13 is further illustrated in Fig. 2.PD 13 includes two photodetector PDAi
And PDBi.Here " A " and " B " indicates channel A and channel B in the dual channel optical encoder of the single track, and " i " is then indicated
For the encoded signal " input " of interpolation device 15 (Fig. 1).Photodetector PDAiAnd PDBiIt is arranged side by side and all has the half of D
(D/2) width.In one embodiment, PDAiAnd PDBiEach of include photodiode array.
Light beam 121 is generated by light source 11, collimated (for example, passing through lens) and is directed to track Tr1.Work as code device
When 16 movement, photodetector PDA is reachediAnd PDBiLight beam be interrupted (or " coding ").In Fig. 2, photodetector PDA is reachedi
Light beam be represented as SAi, and reach photodetector PDBiLight beam be represented as SBi.When code device 16 is mobile, light beam
SAiAnd SBiIntensity according to photodetector PDAiAnd PDBiHow many area is covered and changed by opaque band respectively.It is based on
Tr1 and photodetector PDA as discussed aboveiAnd PDBiConfiguration, optical signalling SAiAnd SBiOut-phase is designed at 90
Degree.
Still referring to Figure 2, there is no opaque regions by track Tr2.In other words, track Tr2 begins in entire code length
It is radioparent eventually.Light beam 122 is generated by light source 11 and is directed to track Tr2.Light beam 121 and 122 may be identical
The different minor beams (beamlet) of collimated light beam.Light beam 122 passes through track Tr2 and becomes optical signalling Sref。
With reference to Fig. 3, which illustrates according to one in the optical encoder 100 with reflection code device 16 of embodiment
The perspective view of a little components.Code device 16 (for example, code wheel or code band) includes two tracks Tr1 and Tr2.Track Tr1, which has, to be handed over
The light reflection replaced and absorption region (or band), they are respectively as indicated by white and dark-coloured space.There is no light suctions by track Tr2
Receive region.In other words, track Tr2 is reflexive always in entire code length.The other aspects of reflection code device 16
It is identical as those of being discussed using the transmission code device 16 in Fig. 2.Collimated light beam 121 and 122 can be by the suitable of light source 11
When optical device is focused.For reasons of clarity, photodetector PDA is not showed that in Fig. 3iAnd PDBi.When 16 edge of code device
When direction 126 is mobile, optical signalling SAiAnd SBiPeriodically it can be interrupted or dim, thus optically to coding
The mobile progress " coding " of device 16.In this embodiment, track Tr1 and photodetector PDAiAnd PDBiIt is configured such that
Optical signalling SAiAnd SBiOut-phase is at 90 degree.
With reference to Fig. 4, the embodiment of the optical modulator 14 constructed according to the aspect of the disclosure is shown.Optics tune
Device 14 processed includes voltage controlled optical modulator 10, divider 17 and optical coupler or optical splitter 12.Optical modulator 14 receives
Baseline optical signal Sref, and in response to optical signalling SrefWith input electrical signal θCNTGenerate two modulated optical signal SAr
And SBr.Here " A " and " B " respectively indicates channel A and channel B, and " r " indicates " base being input in interpolation device 15 (Fig. 1)
It is quasi- " signal.In the shown embodiment, input signal θCNTIt is being used for modulated optical signal SrefThe quilt (in divider 17) before
Divided by positive integer " N ".Integer N is the interpolation factor of interpolation device 15, and can as expected resolution ratio and accuracy be come
Design.Divider 17 can use logic gate, trigger circuit and/or other circuit elements to implement.In this embodiment, voltage-controlled
Optical modulator 10 is numerically controlled light intensity modulator.In a further embodiment, modulator 10 is March-Zehnder
The type of optical modulator (MZM).Therefore, it can also be referred to as MZM 10 in the following discussion.It is, however, to be noted that
The embodiment of modulator 10 is not limited to the modulator of March-Zehnder type.
According to this embodiment, modulator 10 uses numeral input (θCNT) modulated optical signal Sref, thus generate modulation base
Quasi-optics signal Smod.For example, it is first and n-bit binary signal is assigned to n bias voltage by the n-bit two
System input is converted to analog signal, wherein each bit corresponds to a bias voltage.It then applies the bias voltage
In on electrode, the electrode is in turn in optical signalling SrefBy when modulator 10 in optical signalling SrefIn lead to phase shift.Modulation
The output S of device 10modThe cumulative phase shift Δ φ at place is proportional to the summation of input offset voltage at any time.In other words, Δ φ ∝
∫ v (t) dt, wherein v (t) is bias voltage.In one embodiment, it is defeated to be converted to optical signalling by modulator 10 by phase shift Δ φ
S outmodIn Strength Changes.
Fig. 5 illustrates the curve 20 of the Strength Changes of the function as phase shift Δ φ.Optical signalling SmodIntensity in minimum
Intensity ImWith maximum intensity IMBetween change.In this embodiment, sine of the intensity according to one embodiment as phase shift Δ φ
Function and change.Marking below phase axis is n-bit binary system θCNTThe numerical value of/N.For example, when n bit is complete
When portion is 0, phase shift Δ φ is π；When n bit it is all 1 when, phase shift Δ φ be 2 π；It is such.Mark V0,V1,…VnTable
Show the bias voltage that modulator is applied, they correspond respectively to bit bit-0, bit-1 ... bit-n.
Some embodiments of modulator 10 can be found in United States Patent (USP) 4,288,785, be combined by reference
In this.For example, optical modulator shown in Fig. 3 and 5-8 of modulator 10 can the be similar to patent of ' 785 designs.
Referring again to FIGS. 4, modulated optical signal SmodIt is fed to optical coupler/optical splitter 12, the latter is by SmodIt divides
For two optical signalling SArAnd SBr.Signal SBrOptical path further comprise pi/2 optical delay.Therefore, optical signalling SAr
And SBrOut-phase is at 90 degree.In one embodiment, optical coupler/optical splitter 12 is 3dB directional coupler.
With reference to Fig. 6, the schematic block diagram of the PD 13 constructed according to the aspect of the disclosure is shown.PD 13 includes
Four photodetector PDAi、PDBi、PDArAnd PDBr.Each photodetector may include optical diode, optotransistor, grating, light
Lie prostrate battery or other types of electro-optic detector.Each photodetector is able to detect optical signalling and by the optical signalling
Be converted to electric signal.Photodetector PDAiAnd PDBiIt is respectively used to receive encoded optical signals SAiAnd SBi, and they are divided
Coded electrical signal S is not converted toAEiAnd SBEi.Photodetector PDArAnd PDBrThen it is respectively used to receive modulation baseline optical signal
SArAnd SBr, and they are respectively converted into modulation reference electrical signal SAErAnd SBEr。
Photodetector PDAiAnd PDBiSome aspects be discussed by reference to Fig. 2.In one embodiment, light is examined
Survey device PDAiAnd PDBiIt is photodiode, improves the quantum efficiency of corresponding photodetector with gridiron thereon.In this way
A kind of consideration of design be that the resolution ratio of optical encoder 100 depends on photodetector PDAiAnd PDBiSensitivity, because
It is for generating coded electrical signal S for themAEiAnd SBEiPhase difference mechanism a part.In addition, encoded optical signals SAi
And SBiIn luminous intensity may due to light beam reach photodetector PDAiAnd PDBiPass through various optical devices and coding before
Device 16 (for example, see Fig. 2) and may not be ideal.Accordingly, it may be desirable to photodetector PDAiAnd PDBiWith grid-like
Structure (not shown) is to enhance the reception of light on it.Alternatively, photodetector PDAiAnd PDBiOther types can be used
Optical enhancement structure, cone, cylinder, pyramid, quantum dot etc..
As a comparison, photodetector PDArAnd PDBrIt can use and photodetector PDAiAnd PDBiIt is bigger compared to relatively
Freedom degree designs.For example, photodetector PDArAnd PDBrIt is not necessarily arranged side by side, because optical modulator 14 is in optics
Signal SArAnd SBrIn be embedded in phase difference.Moreover, photodetector PDArAnd PDBrIt can be arranged to close to optical modulator
14.Therefore, they do not need grid-like or other types of optical enhancement structure so that optical signalling S is correctly receivedArWith
SBr.In one embodiment, photodetector PDArAnd PDBrAnd optical modulator 14 is fabricated on identical chips with into one
Step improves degree of integration.
Referring still to Fig. 6, PD 13 further comprises two multiplier 5A and 5B and subtracter 6.Two multiplier 5A and
5B can use logic gate, operational amplifier, transistor and/or other circuit elements to implement.Logic can be used in subtracter 6
Door, transistor, operational amplifier, adder and/or other circuit elements are implemented.In this embodiment, multiplier 5A will lead to
The coded electrical signal S of road AAEiWith the modulation reference electrical signal S of channel BBErIt is multiplied and generates multiplication electric signal SA.Similarly,
Multiplier 5B is by the coded electrical signal S of channel BBEiWith the modulation reference electrical signal S of channel AAErIt is multiplied and generates multiplication telecommunications
Number SB.Subtracter is from signal SBSubtraction signal SA, and generate output electric signal Vpe.As discussed below, signal VpeIt can be with
About encoded signal (SAEiAnd SBEi) and modulating reference signal (SAErAnd SBEr) in phase information express.
In this embodiment, modules are designed so that signal SAEi、SBEi、SAErAnd SBErIt is sinusoidal signal.Into one
Step ground, signal SAEiAnd SBEiOut-phase is at 90 degree, and signal SAErAnd SBErOut-phase is at 90 degree.Therefore, they can be expressed as
Under:
SAEi=a*cos θi (1)
SBEi=a*sin θi (2)
SAEr=b*cos θo (3)
SBEr=b*sin θo (4)
In above equation (1)-(4), phase thetaiIt is coded electrical signal SAEiAnd SBEiEntrained phase, and phase thetaoThen
It is modulation signal SAErAnd SBErEntrained phase.Multiplying signal SAAnd SBIt can be expressed as follows:
SA=SAEi*SBEr=ab*cos θi sinθo=(ab/2) * (sin (θi+θo)-sin(θi-θo))
(5)
SB=SAEr*SBEi=ab*cos θo sinθi=(ab/2) * (sin (θi+θo)+sin(θi-θo))
(6)
Vpe=SB–SA=ab*sin (θi-θo)=ab*sin φE (7)
As that can see in equation (7), V is exportedpeCarry encoded signal SAEiAnd SBEiWith modulating reference signal SAEr
And SBErBetween phase error (or phase difference) φEInformation.
Referring back to Fig. 1, signal VpeIt is fed to loop filter (LF) 7.In this embodiment, loop filter 7 is
Low-pass filter with low cutoff frequency, to filter out signal VpeIn high fdrequency component.Due to VpeOnly carry coding letter
Phase error number between modulating reference signal, so the parameter of loop filter 7 can be independently of encoded signal SAEiWith
SBEiOr modulating reference signal SAErAnd SBErFrequency determine.Loop filter 7 can be used logic gate, operational amplifier,
Resistor, capacitor and/or other circuit elements are implemented.Work as phase error phiEAbundant hour carrys out loop filter 7
Output signal e (t) can be expressed as follows:
E (t)=ab* φE (8)
Signal e (t) is fed to EVCO 8.In response to signal e (t), the generation of EVCO 8 can be square-wave pulse or sine
The electric pulse of pulse.The output of EVCO 8 is the interpolated signal output of optical encoder 100.As known in the art, 8 EVCO
It can use resistor, capacitor, varactor, diode, operational amplifier, transistor and/or other circuit elements to come
Implement.In this embodiment, EVCO 8 is voltage-frequency converter, and signal e (t) is applied in the input voltage of EVCO.
In response to signal e (t), EVCO 8 generates the two train of pulse V for respectively representing and being incremented by and successively decreasingo_upAnd Vo_down.For example, Vo_upOn
Pulse can indicate to be incremented by a clockwise direction 1, and Vo_downOn pulse can then indicate to be incremented by 1 (this in a counterclockwise direction
It is 1 identical as successively decreasing in the clockwise direction).In another embodiment, EVCO 8 generates two for respectively representing and being incremented by with direction
Train of pulse VoAnd Vdir(not marked in Fig. 1).For example, VoOn pulse can be according to VdirNumerical value and be incremented by clockwise count or
It counts counterclockwise.Train of pulse from EVCO 8 is sent to external circuit (not shown) to be further processed.
Train of pulse from EVCO 8 is also routed to forward-backward counter 9.Logic gate, touching can be used in forward-backward counter 9
Power Generation Road, transistor and/or other circuit elements are implemented.Forward-backward counter 9 is according to input Vo_upAnd Vo_downAnd upwards or to
Lower counting.As discussed with reference to Figure 4, the numerical value θ of forward-backward counter 9CNTOptical modulator 14 is fed to modulate benchmark
Optical signalling Sref.Phase thetaoAnd θCNTBetween relationship can be expressed it is as follows:
θo=2 π (θCNT/N) (9)
In equation (9), digital N be interpolation factor and also be also Fig. 7 in divider division factor.
Effectively, PD 13, LF 17, EVCO 8, forward-backward counter 9 and optical modulator 14 form phaselocked loop, coding
Signal SAEiAnd SBEiWith modulating reference signal SAErAnd SBErBetween phase error phiEIt is minimized by the phaselocked loop.By
In the PLL in the loop include optical module and electric component, so it is quasi-optics PLL (QOPLL).When the QOPLL reaches
When steady state operation, optical signalling SArAnd SBrIn Phase Tracking (or being locked as) optical signalling SAiAnd SBiPhase.For
Their electrical counterpart is same, i.e. electric signal SAErAnd SBErIn Phase Tracking (or being locked as) optical signalling SAEiWith
SBEiPhase.The embodiment of optical encoder 100 can provide excellent noise inhibiting ability and can answer various
With --- such as the controller of high-precision servo mechanism and the machine mobile with high-speed numeric control --- middle use.
With reference to Fig. 7-9, the method 200 for being used to execute optical encoding of the aspect according to the disclosure is shown.Method
200 can implement by or using optical encoder 100 in whole or in part.It should be understood that before method 200,
During and after additional operations can be provided, and described some operations can for this method additional embodiment and by
Replacement, elimination or mobile.Method 200 is only example and is not intended to the sheet to the range being expressly recited beyond claim
It is open to limit.Method 200 is discussed below in conjunction with Fig. 1-6 (when needed).
In operation 202, method 200 (Fig. 7) generates the first and second encoded optical signals and uncoded reference light from light source
Signal is learned, wherein the first and second encoded optical signals out-phase is at 90 degree.Use optical encoder 100 (Fig. 1) as showing
Example, method 200 generate the first and second encoded optical signals S using the track Tr1 of light source 11 and code device 16AiAnd SBi。
In order to further illustrate the example, method 200 generates baseline optical signal using the track Tr2 of light source 11 and code device 16
Sref。
In operation 204, method 200 (Fig. 7) modulates the uncoded baseline optical signal using electric signal, thus generates tune
Baseline optical signal processed.Using optical modulator 14 (Fig. 4) as an example, method 200 uses numerically controlled optical modulation tune
Device 10 processed utilizes electric signal θCNTOr θCNTDerivative form modulate baseline optical signal Sref.For example, θCNTDerivative shape
Formula can be θCNTIt is divided by the version of N, wherein N is greater than 1 integer.
In operation 206, method 200 (Fig. 7) generates the first and second modulated opticals letter from the modulation baseline optical signal
Number, wherein the first and second modulated opticals signal out-phase is at 90 degree.Still use optical modulator 14 (Fig. 4) as showing
Example, method 200 generate the first and second modulated optical signal S using 1x2 optical coupler/optical splitter 12ArAnd SBr, they
Out-phase is at 90 degree.
In operation 208, first and second encoded optical signals are respectively converted into first and the by method 200 (Fig. 7)
Two coded electrical signals.In operation 210, the first and second modulated opticals signal is respectively converted into first by method 200 (Fig. 7)
With the second modulation signal.Using phase detectors 13 (Fig. 6) as an example, method 200 uses four photodetector PDAi、
PDBi、PDArAnd PDBrRespectively by optical signalling SAi、SBi、SArAnd SBrBe converted to electric signal SAEi、SBEi、SAErAnd SBEr。
In operation 212, first coded electrical signal and the second modulation signal are multiplied, thus produce by method 200 (Fig. 8)
Raw first multiplication electric signal.In operation 214, method 200 (Fig. 8) is by second coded electrical signal and the first modulation signal phase
Multiply, thus generates the second multiplication electric signal.Still phase detectors 13 (Fig. 6) is used as an example, method 200 uses multiplier
5A is by signal SAEiAnd SBErIt is multiplied to produce multiplying signal SA, and use multiplier 5B by signal SBEiAnd SAErIt is multiplied to produce
Multiplying signal SB。
In operation 216, method 200 (Fig. 8) subtracts the first multiplication electric signal from the second multiplication electric signal, by
This generates the second electric signal.Still phase detectors 13 (Fig. 6) is used as an example, method 200 uses subtracter 6 from signal SB
Subtraction signal SA, generate electric signal Vpe, carry the phase error between the coding and modulated signal.
In operation 218, method 200 (Fig. 8) obtains first electric signal from second electric signal, and makes described the
One modulation signal tracks first coded electrical signal.Using optical encoder 100 (Fig. 1) as an example, method 200 is from letter
Number VpeObtain signal θCNT, and make the modulated signal SAErAnd SBErTrack the encoded signal SAEiAnd SBEi.Fig. 9 is illustrated
Operation 218 according to embodiment comprising four sub-operations 230,232,234 and 236.
With reference to Fig. 9, in sub-operation 230, operation 200 is using the low-pass filter of such as LP 7 (Fig. 1) to the second electric signal
It is filtered, thus generates the second electric signal through filtering.LP7 filters out the high fdrequency component of the second electric signal and allows its low
Frequency component passes through.In sub-operation 232, method 200 uses the voltage-controlled vibration of such as EVCO 8 in response to the second electric signal through filtering
It swings device and generates electric pulse.In sub-operation 234, method 200 is using the forward-backward counter of such as forward-backward counter 9 to the electric pulse
Quantity is counted, and counting is thus generated.In sub-operation 236, which divided by positive integer, is thus generated first by method 200
Electric signal.
Although being not intended as limiting, one or more other embodiments of the present disclosure are directed to optical encoder or interpolation
Device provides many benefits.For example, embodiment of the disclosure provides a kind of novel quasi-optics (or quasi- electrical) PLL
(QOPLL).Each embodiment provides high frequency response and noise suppressed, and improves the interpolation factor of interpolation device.According to this
The interpolation device of open embodiment can provide twice or more compared with conventional interpolation device of interpolation factor in some applications.Separately
Outside, it some embodiments and is not used as the ROM and the so much chip or plate face area of look-up table in existing electric interpolation device.Cause
This, such embodiment can more be economically fabricated than conventional reference object.This can result in high-resolution compact
And cost-effective optical encoder.
In an illustrative aspect, this disclosure relates to a kind of equipment.The equipment includes optical modulator, is configured as
The first and second modulated optical signals are generated in response to the first electric signal and baseline optical signal.The equipment further comprises
Phase detectors are configured as receiving the first and second encoded optical signals and the first and second modulated opticals signal,
And generate the second electric signal for indicating the phase difference between the encoded optical signals and the modulated optical signal.It is described to set
Standby further comprises voltage controlled oscillator, is configured to respond to second electric signal and generates electric pulse.The equipment is into one
Step includes counter, is configured as counting the quantity for the electric pulse for carrying out voltage controlled oscillator, thus generates counting,
In go to the optical modulator the first electric signal include it is described counting or the counting derivative form.
In another illustrative aspect, this disclosure relates to a kind of equipment.The equipment includes in response to the first telecommunications
Number and baseline optical signal and generate the devices of the first and second modulated optical signals.The equipment further comprises for responding
The device of the second electric signal, institute are generated in the first and second encoded optical signals and the first and second modulated opticals signal
The second electric signal is stated to indicate between first and second encoded optical signals and the first and second modulated opticals signal
Phase difference.The equipment further comprises the device for generating electric pulse in response to second electric signal, and for producing
The device of the counting of the raw electric pulse, wherein first electric signal includes the counting for being divided by positive integer.
In another illustrative aspect, this disclosure relates to a kind of method of optical encoding.The method includes producing from light source
Raw first and second encoded optical signals and uncoded baseline optical signal, wherein first and second encoded optical signals are different
It coordinates 90 degree.The method further includes modulating the uncoded baseline optical signal using the first electric signal, thus generate
Modulate baseline optical signal.The method further includes generating the first and second modulation lights from the modulation baseline optical signal
Signal is learned, wherein the first and second modulated opticals signal out-phase is at 90 degree.The method further includes by described first
The first and second coded electrical signals are respectively converted into the second encoded optical signals.The method further includes by described first
The first and second modulation signals are respectively converted into the second modulated optical signal.The method further includes by described first
Coded electrical signal and the second modulation signal are multiplied, and thus generate the first multiplication electric signal.The method further includes by institute
It states the second coded electrical signal and the first modulation signal is multiplied, thus generate the second multiplication electric signal.The method is further wrapped
It includes and subtracts the first multiplication electric signal from the second multiplication electric signal and thus generate the second electric signal, and from described
Two electric signals obtain first electric signal, and first modulation signal is made to track first coded electrical signal.
Foregoing has outlined the feature of several embodiments thus those skilled in the art can better understand that the side of the disclosure
Face.Artisan will appreciate that they will can design or modify use based on the disclosure easily
In the other processes and structure of the identical purpose and/or the identical advantage of realization that execute embodiment defined herein.Art technology
Personnel will also appreciate that such equivalent constructions without departing from spirit and scope of the present disclosure, and they can make herein
Various change, replacement and change are without departing from spirit and scope of the present disclosure out.
Claims (20)
1. a kind of equipment, comprising:
Optical modulator is configured to respond to the first electric signal and baseline optical signal and generates the first modulated optical signal
With the second modulated optical signal；
Phase detectors are configured as receiving the first encoded optical signals and the second encoded optical signals and first modulation
Optical signalling and the second modulated optical signal, and generate instruction first encoded optical signals and the second coded optical
Second electric signal of the phase difference between signal and the first modulated optical signal and the second modulated optical signal；
Voltage controlled oscillator is configured to respond to second electric signal and generates electric pulse；With
Counter is configured as counting the quantity of the electric pulse from the voltage controlled oscillator, thus generate
It counts, wherein first electric signal for going to the optical modulator includes the derivative form of the counting or the counting.
2. equipment according to claim 1, wherein the phase detectors include:
First photodetector and third photodetector are configured as first encoded optical signals and the second coded optical
Signal is respectively converted into the first coded electrical signal and the second coded electrical signal；
Second photodetector and the 4th photodetector are configured as the first modulated optical signal and the second modulated optical
Signal is respectively converted into the first modulation signal and the second modulation signal；
First multiplier is configured as that first coded electrical signal is multiplied and is generated with second modulation signal
First multiplication electric signal；
Second multiplier is configured as that second coded electrical signal is multiplied and is generated with first modulation signal
Second multiplication electric signal；With
Device is configured as subtracting the first multiplication electric signal from the second multiplication electric signal, thus generates described
Two electric signals.
3. equipment according to claim 1, further comprises:
Loop filter is coupled with the phase detectors, and is configured as in second electric signal by described voltage-controlled
Oscillator passes through the low frequency component of second electric signal before receiving.
4. equipment according to claim 1, wherein the voltage controlled oscillator includes voltage-frequency converter.
5. equipment according to claim 1, wherein going to first electric signal of the optical modulator by by institute
It states and counts divided by the integer greater than 2 and obtained from the counting.
6. equipment according to claim 1, wherein the first modulated optical signal and the second modulated optical signal
Out-phase is at 90 degree, and first encoded optical signals and the second encoded optical signals out-phase are at 90 degree.
7. equipment according to claim 1, wherein the optical modulator includes:
Numerically controlled light intensity modulator, be configured to respond to first electric signal and the baseline optical signal and
Generate third modulated optical signal；With
Optical coupler or optical splitter are configured to respond to the third modulated optical signal and generate first modulation
Optical signalling and the second modulated optical signal.
8. equipment according to claim 1, further comprises:
Light source is used to guide the first light beam to the first track to generate first encoded optical signals and described second and compile
Code optical signalling, and for guiding the second light beam to the second track to generate the benchmark for going to the optical modulator
Optical signalling.
9. equipment according to claim 8, wherein first light beam is conducted through first track to generate
The first encoded optical signals and second encoded optical signals are stated, and second light beam is conducted through second rail
The baseline optical signal of the optical modulator is gone in road to generate.
10. equipment according to claim 8, wherein first light beam generates described from first track reflection
One encoded optical signals and second encoded optical signals, and second light beam from second track reflection to generate
Go to the baseline optical signal of the optical modulator.
11. a kind of equipment, comprising:
First device is adjusted for generating the first modulated optical signal and second in response to the first electric signal and baseline optical signal
Optical signalling processed；
Second device, for believing in response to the first encoded optical signals and the second encoded optical signals and first modulated optical
Number and the second modulated optical signal and generate the second electric signal, second electric signal indicates the first coded optical letter
Phase number between second encoded optical signals and the first modulated optical signal and the second modulated optical signal
Potential difference；
For generating the device of electric pulse in response to second electric signal；With
For generating the device of the counting of the electric pulse, wherein first electric signal includes the meter for being divided by positive integer
Number.
12. equipment according to claim 11, further comprises:
For the first light beam being guided to the first track to generate first encoded optical signals and second coded optical
Signal and the second light beam is guided to the second track to generate the device for the baseline optical signal for going to first device
Part, wherein first track and second track are on identical code device.
13. equipment according to claim 12, wherein first track includes that alternate light transmission region and light are impermeable
Area pellucida domain, and second track does not have light opaque region.
14. equipment according to claim 12, wherein first track includes alternate reflection region and light absorption
Region, and second track does not have photo-absorption region.
15. equipment according to claim 11, wherein for generating the first modulated optical signal and the second modulated optical letter
Number the device include voltage controlled optical modulator and be coupled to the voltage controlled optical modulator output optical splitter.
16. equipment according to claim 11, wherein second device includes:
For generating the first coding electricity respectively responsive to first encoded optical signals and second encoded optical signals
The first light detecting device and third light detecting device of signal and the second coded electrical signal；
For generating the first modulation electricity respectively responsive to the first modulated optical signal and the second modulated optical signal
The second light detecting device and the 4th light detecting device of signal and the second modulation signal；
For first coded electrical signal to be multiplied with second modulation signal, the first multiplication electric signal is thus generated
Device；
For second coded electrical signal to be multiplied with first modulation signal, the second multiplication electric signal is thus generated
Device；With
For subtracting the first multiplication electric signal from the second multiplication electric signal, second electric signal is thus generated
Device.
17. a kind of method, comprising:
The first encoded optical signals and the second encoded optical signals and uncoded baseline optical signal are generated from light source, wherein described
First encoded optical signals and the second encoded optical signals out-phase are 90 degree；
The uncoded baseline optical signal is modulated using the first electric signal, thus generates modulation baseline optical signal；
The first modulated optical signal and the second modulated optical signal are generated from the modulation baseline optical signal, wherein described first
Modulated optical signal and the second modulated optical signal out-phase are 90 degree；
First encoded optical signals and second encoded optical signals are respectively converted into the first coded electrical signal and
Two coded electrical signals；
The first modulated optical signal and the second modulated optical signal are respectively converted into the first modulation signal and
Two modulation signals；
First coded electrical signal is multiplied with second modulation signal, thus generates the first multiplication electric signal；
Second coded electrical signal is multiplied with first modulation signal, thus generates the second multiplication electric signal；
The first multiplication electric signal is subtracted from the second multiplication electric signal, thus generates the second electric signal；And
First electric signal is obtained from second electric signal, and the first modulation signal tracking described first is compiled
Code electric signal.
18. according to the method for claim 17, wherein showing that first electric signal includes: from second electric signal
Second electric signal is filtered using low-pass filter, thus generates the second electric signal through filtering；
Electric pulse is generated using voltage controlled oscillator in response to second electric signal through filtering；
It is counted using quantity of the forward-backward counter to the electric pulse, thus generates counting；And
By the counting divided by positive integer, to obtain first electric signal.
19. according to the method for claim 17, wherein generating first encoded optical signals and described from the light source
Second encoded optical signals and the uncoded baseline optical signal include:
First light beam is guided to as the first track on the device of code wheel or code band, wherein first track includes alternating
Light transmission region and light opaque region；And
Second light beam is guided into the second track to described device, wherein second track only has light transmission region.
20. according to the method for claim 17, wherein generating first encoded optical signals and described from the light source
Second encoded optical signals and the uncoded baseline optical signal include:
First light beam is guided to as the first track on the device of code wheel or code band, wherein first track includes alternating
Reflection region and photo-absorption region；And
Second light beam is guided into the second track to described device, wherein second track only has reflection region.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US15/332,615 US9887781B1 (en) | 2016-10-24 | 2016-10-24 | High resolution interpolator for optical encoder |
| US15/332,615 | 2016-10-24 | ||
| PCT/US2017/057717 WO2018080935A1 (en) | 2016-10-24 | 2017-10-20 | High resolution interpolator for optical encoder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110178322A true CN110178322A (en) | 2019-08-27 |
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ID=61027315
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201780065692.XA Pending CN110178322A (en) | 2016-10-24 | 2017-10-20 | High-resolution interpolation device for optical encoder |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US9887781B1 (en) |
| EP (1) | EP3529923A4 (en) |
| CN (1) | CN110178322A (en) |
| WO (1) | WO2018080935A1 (en) |
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| CN110658834B (en) * | 2019-09-03 | 2023-01-13 | 中国航空工业集团公司西安飞行自动控制研究所 | Implementation method and device for setting target parameters of telex flight control system |
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Also Published As
| Publication number | Publication date |
|---|---|
| WO2018080935A1 (en) | 2018-05-03 |
| EP3529923A1 (en) | 2019-08-28 |
| US9887781B1 (en) | 2018-02-06 |
| EP3529923A4 (en) | 2020-06-24 |
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